No exploitation reportedFix available

CVE-2021-3448

No exploitation reported by the sources we read.

Published2021-04-08
WeaknessCWE-358

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.

Timeline

dates in UTC

2021-04-0823:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-3448?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-3448?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Fedoraproject fedora

Branch	Affected	Fixed in	Source
32.x	= 32	no fix published	NVD
33.x	= 33	no fix published	NVD
34.x	= 34	no fix published	NVD

Oracle communications cloud native core network function cloud native environment

Branch	Affected	Fixed in	Source
1.9	= 1.9.0	no fix published	NVD

Redhat enterprise linux

Branch	Affected	Fixed in	Source
8.0	= 8.0	no fix published	NVD

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

dnsmasqAlmaLinux:8all versions · fixed in 2.79-19.el8and 1 other package

Vendor advisories

CVE-2021-3448 Red Hat Product Security21 products fixed · 6 known affected
dnsmasq: fixed outgoing port used when --server is used with an interface name
dnsmasq as a component of Red Hat Enterprise Linux 6 · dnsmasq-utils as a component of Red Hat Enterprise Linux 6 · dnsmasq.src as a component of Red Hat Enterprise Linux 6 · +3 more
RHSA-2021:4153 Red Hat Product Security21 products fixed
Red Hat Security Advisory: dnsmasq security and bug fix update

Full record on NVD

Fix

Vendor fix Red Hat Product Security RHSA-2021:4153 · 21 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Workaround from the vendor Red Hat Product Security RHSA-2021:4153 · 21 productsThe flaw can be prevented by removing `--server=<address>@<interface>` option or by removing the directive `server=<address>@<interface>`. If dnsmasq is being run through NetworkManager, please be aware that NetworkManager automatically configures dnsmasq to use the `server=<address>@<interface>` d…
No fix planned, says the vendor Red Hat Product Security CVE-2021-3448 · 6 productsOut of support scope

Advisories and patches

bugzilla.redhat.comPatch
www.oracle.comPatch

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2025-12-03
OpenCVESSVC decisionnone—
CISA-ADPCVSS 3.142025-12-03
NVDCVSS 3.14read 2026-10-23
NVDCVSS 2.04.3read 2026-10-23
CNAweakness (CWE)CWE-358read 2026-10-23
FIRST EPSSEPSS score2.3 %2026-10-22
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
Published: 2021-04-08
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-3448?

Is CVE-2021-3448 actively exploited?

Active exploitation of CVE-2021-3448 has not been confirmed. Its EPSS score was 2.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-3448?

CVE-2021-3448 has a CVSS v3 base score of 4 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N.

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